Telegraph repeating system



Oct' 6, 1936. F. s. KINKEAD ET Al. 2,056,277

TELEGRAPH REPEATING SYSTEM ESMA/Km0 /NI/E/VTORS 6. A'LOCKE Patented oei.6, 193e` 2,056,27 7

vUNITED STATES PATENT OFFICE TELEGRAPH REPEATING SYSTEM Fullerton S.Kinkead, Ridgefield Park, N. J., and

George A. Locke, Glenwood Landing, N. Y., assignors to Bell TelephoneLaboratories, Incorporated, New York, N. Y., a. corporation of New YorkApplication July 24, 1935, Serial No. 32,866

13 Claims. (Cl. 1'18-73) This invention relates to telegraph repeatingis also made whereby a break signal may be apsystems and. moreparticularly to systems of this plied -to all of the interconnectedrepeaters and type in which a plurality of stations are contheirassociated lines for well-known purposes.

nected together for intercommunicetion between In accordance With a morespecific feature of them. the invention, the local sides of two or more5 Itis en object of the invention to provide greatrepeaters areinterconnected by a one-wire Signal er flexibility in repeating systemsin the intercircuit and in a preferred embodiment of the inconnectionoi' lines of similar or different char- VentiOn this circuit constitutesa multiple, which acteristics than has hitherto been available.appropriately may be termed the hub, since it lo Itis a further objectto provide a repeating arhas a COmInOn peint 0r Center from which the 10rangement whereby n, large number of lines may connections may be saidto radiate like spokes be interconnected in e, simp1e manner and with..to the individual repeaters. It should however be out introducing signaldistortion or reducing the underStOOd that the local Sides may beinterconspeed of operation. nected by a one wire series circuit fortwo-way lo' It is a further object of the invention to procommunicationbetween the signaling circuits. 15 vide a repeating arrangement wherebylines may It is a further specific feature of the invention be added toor disconnected from an estabushed that the common multiple connection,or hub, is set-up between a plurality of lines which remain normallyconnected to equipotential points in the in circuit and without thenecessity for making Various repeaters and thi-IS iS WithOllt Signaling.,0 adjustments to prevent disturbances. current during an al1-markingcondition. When 2c It is a still further object of the invention to anyOne repeater. by the COIltaCtS 0f its receiving standardize theappearance of all lines and loops relay, applies spacing potential tothe hub circuit, of greatly differing characteristics at a repeatersignaling current will flow therein and the restation so as tofacilitate their interconnection. mailling repeaters Will be Operated inmultiple t0 It is a. still further object of the invention to repeat thespacing condition into their line cirreduce to a minimum or eliminatealtogether the cuits by means 0f their transmitting relays.

adjustment of repeaters for bias and ba1anee It is a further feature ofthe invention that the correction when two or more circuits are beingcircuit elements in the local side of each repeater interconnected. areof xed value and require no adjustment In accordance with the invention,all line cirwhen connection is made with one or more other 30 cuits andall loop circuits appearing at a repeater repeaters, since the localcircuit is of negligible station are permanently terminated inindividimpedance and the windings of the transmitting ual two-wayrepeaters and two or more lines or relays are connected in multipleduring spacing loops are interconnected by interconnection of condition.The circuit elements in the line side their repeaters. of the repeatermay also be xed except that In accordance with a feature of theinvention, provision may be made for keeping the normal one side, theiine slde of each repeater circuit line current constant when necessary;this is posis adapted for and initially adjusted to the parsible sincethe repeater is permanently associated ticular requirements of the linecircuit to which with its line circuit.

it is permanently assigned and the other side, the The invention in itspreferred form is particu- 40 local side, is adapted for interconnectionwith the larly adapted for interconnection of a comparalocal sides oione or more other repeaters. tively large number of line or loopcircuits. In

In accordance with another feature of the inview of the fact that only asingle conductor of vention, the local side oi a repeater is connectedeach repeater needs be connected to similar single 4;, in circuit withthe local side of one or more other conductors of other repeaters makesit obvious 45 repeaters in such a manner that during marking that suchinterconnection can be made by very condition all of the interconnectedrepeaters essimple means. tablish a marking condition in theirassociated Thus, in the case of a so-called lease set-up, line orsignaling circuits and any one of the the single wire connections orspokes may be di- :ic repeaters, when operated to spacing by itsassorectly soldered or clamped together; by means of ciated linecircuit. will operate the remaining a simple jack in the spoke of eachrepeater, the repeaters to establish a spacing condition in theirrepeater may be disconnected from the interrespective line circuits.Provision is furthermore connection or hub and through a patching cordmade for preventing the repeater from interferconnected to any othercircuit, such as a line ing with the signals incoming thereto. Provisioncircuit or a monitoring circuit.

In the case-of the ordinary appearance of a line in a switchboard, theinterconnection with another line, made on request to an operator, maybe established by the plugging in of a single-wire patching cord, andconnection to other lines may be simultaneously set up through simplemultiple Jacks and other patching cords or in any other convenientmanner.

The arrangement is particularly suitable for automatic set-up ofinterconnections, as by relays or by more complicated switching means,since only a single connection need be established for each line and itsrepeater. It is furthermore evident that the interconnection of a greatnumber of lines for broadcast purposes would be greatly facilitated bythe use of the invention.

The invention will now be described in one oi its preferred forms andreference will be made to the accompanying drawings, in which:

Fig. l illustrates a telegraph repeater system for interconnection of aplurality of signaling circuits by means of a multiple circuit, and

Fig. 2 shows an example of a similar circuit in which the signalingcircuits are interconnected by a. series circuit. p

Referring particularly to Fig. l, an interconnecting system is shownwhich comprises a line circuit L1 connected through a repeater A, a linecircuit L2 connected through repeater B, and a line circuit L3 connectedthrough repeater C to an interconnecting circuit or hub H.

The lines L1 and L2 are two-way loop circuits connected to subscribersstations S, which usually would be equipped with teletypewriters havinga polarized receiving winding and transmitting contact means. Therepeaters A and B are each equipped with receiving relays R1 and R2 andsending relays S1 and S2, respectively. A suitable source of positiveand negative potential is connected to the line side of the repeaters Aand B.

For the transmission of signals into the line circuit L1; the relay S1is operated to its marking and spacing contacts, thereby applyingnegative and positive potential alternately through the differentiallyWound relay R1, which remains .unaffected The signals continue over theline circuit through the subscribers station and back to positivepotential at the repeater A. Signals originating at the subscribersstation are transmitted by opening and closing the line at the keyboardcontacts. In this case, the line winding of relay R1 becomes alternatelydeenergized and energized and the relay is operated to its spacing andmarking contacts by its biasing winding in a well-known manner.

The local side of the repeaters is supplied with current from a suitablesource, which may be a battery, over the common conductors B+ and B-. Itis, of course, possible for this purpose to use the same source as isused for the line side of the repeater.

Referring particularly to the repeater A, the sending relay S1 has Vanormally energized winding connected to conductors B+ and B- foroperating the relay to its marking contact. The other winding on relayS1 is connected from conductor B- over the marking contact of thereceiving relay R1 and the spoke connection SP1 to the hub H. Therepeater B has a similar connection for the left-hand winding of relayS2, over the marking contact of relay R2 and spoke connection SP2 to thehub H. Similar connec- -tions may be traced through the repeater C andthis system, each connection beginning at conductor'B- and ending at thehub H.

It will thus be seen that when all the repeaters are in markingcondition, the hub H will be connected to the same potential in eachrepeater and that no signaling current will be iiowing in the windingsof the sending relays or in the hub circuit so long as this condition ismaintained.

When a spacing signal arrives over line L1 to operate relay R1 tospacing, the circuit through the winding of relay S1 will be opened sothat this relay will remain unaffected. In spacing position of relay R1,a circuit is closed from conductor B+ to the hub H, which thus appliespositive potential to all the windings of sending relays in otherrepeaters, such as B and C, thereby operating those sending relays fortransmission oi.' a spacing impulse over their associated line circuits.To trace one of these circuits, the B+ conductor is connected overspacing contact of relay R1, spoke connection SP1, hub H, spokeconnection SP2, marking contact of relay R2, winding of sending relay Szto conductor B-.

When line L1 is again closed, relay R1 returns to marking, disconnectingconductor B+ from the hub circuit and thereby deenergizing all theleft-hand windings of the sending relays in the other repeaters whichthen will be operated to marking by their biasing windings. In repeaterA, the sending relay S1 will again be connected into the hub circuitready for reception of signals from another repeater.

It is evident that each station may continue to send until anotherstation applies a break signal which will connect the hub H to conductorB+ for its duration and thus cause all of the sending relays to operateto spacing for transmission of similar break signals to their associatedlines.

The repeater C is a modification of the repeaters A and B, adapted forfour-wire operation on its line side. The line conductors L3 may beconnected through one-way repeaters to cable pairs, or to a single cablepair through a hybrid circuit, or the line conductors L3 may be directlyconnected to cable pairs-or to any other desired arrangement. Signalsincoming over the line circuit La will operate the receiving relay R4to, in turn, operate receiving relay Ra which will impress correspondingimpulses upon the hub circuit. Signals from the hub circuit will operatesending relay S3 to retransmit signals over the outgoing circuit of theline La.

With the repeater C in marking condition, relay S3 is normally held tomarking by its biasing winding; the left-hand winding of relay S3 iscontinuously energized from conductor B- through right-hand winding andmarking contact of receiving relay R3, spoke conductor SP3 to the hub H.With the other repeaters also in marking condition, no current will flowin this circuit. As soon as spacing potential from conductor B+ isapplied to the hub by any other repeater, the right-hand winding ofrelay Rx becomes energized to prevent this relay from vbeing operated tospacing by the line circuit and the left-hand winding of relay S3becomes energized for transmission of a spacing impulse over theoutgoing circuit of the line L2. l

From the description given above, it will be apparent that all signalingbetween the local side of all repeaters takes place over a singleconductor circuit comprising the spokes SP1, SP2, etc. and the hubconductor H, and that, therefore, all switching operations for addingrepeaters to a hub circuit or for removing them there- 75 from will beconfined to a single conductor for each repeater.- This makes itpossibleA to ar.- range all repeaters on bays and to arrange theapparatus necessary for making the interconnection on a switchboard ortestboard, removed from the repeaters, without resort to an excessivenumber of wires. The spokes SP may, of course, be soldered directly tothe hub at points P for the permanent interconnection of certain linesas in the case of a lease set-up. However, in this case it is convenientto arrange contact means C1, C2, Ca, respectively, for disconnection ofany repeater from the hub circuit, and temporary connection, forexample, to a'monitoring equipment, or to some other line circuit uponspecial request. The switching means C1, C2, C3 may each comprise a jackon a switchboard for connection by means of suitable patching cordsy toone or more other line circuits; or the switching means may be thecontacts of a relay or of a more complex switching device for manualremote control of the set up.

A convenient arrangement of such a switching means is shown at C4 inconnection with a repeater D which may be of the same type as repeater Aor repeater C. In this arrangement, two jacks, J1 and J2, are providedwith normally closed tip contacts included in the spoke circuit SP4. Byinsertion of the plug PL in jack J1, the repeater D with its linecircuit will be separated from the hub H and may be connected through acord attached to the plug to another jack for monitoring purposes or forcommunication with another line and repeater circuit. By insertion ofthe plug PL in jack J2, the repeater D will also be separated from thehub and the cord will be connected to the hub, as for test purposes.

It should, of course, be understood that oneway line circuits also maybe connected through a simple one-way repeater, such as a polar relaycorresponding to the sending relay illustrated in the drawings, fortransmission of impulses from the hub circuit into the line circuit; inthe case of a short line, the line may even be connected directly to thehub circuit through a suitable network. y It should, furthermore, beunderstood that any one of the line circuits may be replaced by a localoperators circuit, which thus may be adapted for one-way or two-wayoperation as desired.

As has already been stated above, the assignment of a repeater to eachline circuit has the basic advantage that lines of differentcharacteristics may be properly equipped by provisions in the line sideof the individual repeaters, and that the local side of the repeaterswill be practically independent of the line requirements and may beunified for cooperation with a great number of other repeaters over alocal circuit.

The arrangement shown in Fig. 2 is an example of how the local sides ofpermanently assigned repeaters may be interconnected in a series circuitwhich includes a winding and a contact of each repeater and is normallyclosed by all the contacts during marking condition and opened fordeenergization of all windings by the opening of any one of the contactsduring spacing condition.

The circuit shown in Fig. 2 is analogous to that shown in Fig. 1 andshows lines L1 and L2 from subscribers stations S interconnected throughrepeaters A and B to the hub circuit H. The four-conductor line L3 i sconnected through what may be termed a terminating interconnectingrepeater C to the hub circuit.

The local sides of the repeaters are, in this instance, seriallyincluded in the hub circuit. 'I'his circuit may be traced from batteryover conductor B+, marking contact of receiving relay Ra, right-handwinding of sending relays S3 and S4, hub conductor H, marking contact ofrelay Rz, right-hand winding of relay S2, hub conductor H, markingcontact of relay R1 righthand winding of relay S1, hub conductor Hmarking contact and winding of other repeaters in similar seriescircuits, and conductor B- back to battery.

With this series hub circuit in all-marking condition, current will ilowin this circuit to operate the S relays into marking position forapplication of marking potential to their respective line circuits. Whenany one of the receiving relays is operated to spacing in response to anincoming spacingy signal, the series circuit is opened and all the Srelays will be operated to spacing by their bias windings.

Considering now one of the subscribers repeaters and referringparticularly to repeater A of Fig. 2., the sending relay.S1 normallyreceives an operating current to marking in its righthand winding and anoperating current to spacing in its left-hand winding, the ampere turnsof these two windings being such that they, in marking condition,neutralize one another; the center or biasing winding receives a holdingcurrent of a direction depending upon the position of the armature butalways in a direction to hold the armature in its position. Thus, undermarking conditions, the biasing winding has sole control of the relayand is holding it to marking.

When a spacing signal is transmitted over the line L1 by opening of thecontact at the substation, the receiving relay R1 is operated to spacingby its biasing winding. Immediately upon opening of the line, thecurrent in the left-hand winding of relay S1 is reduced to zero; thiswinding is shunted by resistance i5 and thus carries less current thanthe right winding of receiving relay R1, for which reason the current inthe left winding of relay S1 will reduce to zero sooner than the currentinthe right winding of relay R1, or before relay R1 reaches its spacingcontact. When the marking contact of relay R1 opens, the current in theright-hand winding of relay S1 reduces to zero; this reduction will bedelayed by the spark protection condenser li which tends to maintainthis current for a short'time. By this arrangement, the relay S1 may beprevented from operating to spacing when a spacing signal is receivedover the line.

When a spacing signal is received over one of the other repeaters torender the hub circuit currentless, the right-hand winding or relay S1in repeater A will become currentless; the line current in the left-handwinding of relay S1 then is strong enough to overcome the biasingwinding and operate relay S1 to spacing. When the marking contact opens,the line current is reduced; however, due to the spark protectioncondenser l3, the current will be temporarily maintained in theleft-hand winding of relay S1 to insure that the armature will continueits travel and engage the spacing contact of S1. With the armature inspacing position, the current is reversed in the biasing winding ofrelay S1 for holding the armature in position. A similar conditionobtains in relay R1 where the current in the right-hand winding will bemaintained until relay S1 reaches its spacing contact; by that time, thecurrent in the left-hand or biasing winding ot relay R1 will be reversedto aid the line current in maintaining the amature in marking position.

When a marking condition is established in the hub circuit, the currentwill again flow in the right-hand winding oi' relay Si, and will besumcient to overcome the biasing current in the center winding andoperate the relay to marking. As the armature of relay Si leaves thespacing contact, a. charging current through condenser I2 willtemporarily maintain the biasing current towards marking in relay R1until the armature of relay S1 reaches marking position, when the linecurrent will hold relay R1 to marking and permit the biasing current toreverse without ail'ecting the relay. When the armature of relay S1reaches marking position, the current in its biasing winding isreversed, simultaneously with the establishment of current in theleft-hand line winding, to aid the right-hand winding in holding therelay to marking.

Referring now to the repeater station C shown in Fig. 2, a spacingsignal incoming over the lower branch of line L3 will operate relay R4to spacing, which in turn will operate receiving relay R3 to spacing andreverse the current in lefthand or biasing winding of sendingrelays S3and S4.

When relay R: opens the hub circuit through the right-hand windings ofsending relays S3 and S4, these relays will be held in marking positionby the reversed biasing current. When relay R4 is again operated tomarking, relay R3 will operate to marking and close the hub circuit tohold relays Sa and S4 in marking position; the biasing current in theserelays will be temporarily maintained due .to the charging of condenser33 when the spacing contact of relay R4 is opened; in this manner falseoperation of relays Sa and S4 before relay R3 reaches its markingcontact may be prevented.

When the hub circuit is opened at some other repeater the relays Ss andS4 will be operated to spacing by their biasing windings; relay S3transmits a spacing signal over the upper portion of line L3 and relayS4 applies negative potential to the spacing contact of relay R4 toprevent operation of relay R3 at this time.

Even though the spoke circuit from each repeater comprises twoconductors, the contact of switching means C1, C2 and C3 for associatingthe repeaters with the hub circuit may be arranged in the same manner asdescribed for the circuit shown on Fig. l.

What is claimed is:

l. A telegraph signaling system comprising a plurality of at least threetelegraph lines each having terminating repeating means, and a multipleconnection between all of said repeating means for intercommunicationbetween said lines through their associated repeating means.

2. A telegraph signaling system comprising a telegraph line havingtwo-way terminating repeating means, a plurality of other telegraphlines each having terminating repeating means, a signaling connectionfrom the repeating means for said one line connecting the repeatingmeans for said plurality of lines in multiple for passing of signalsbetween said one line and said plurality of lines.

3. A telegraph signaling system comprising a plurality of at least threesignal repeating means each having a line side and a local side fortwoway transmission, line circuits each connected to one of said linesides, and a common multiple connected to the local side of all 'of saidplurality of repeating means for two-way communication between all oisaid line circuits through said repeating means.

4. A telegraph signal repeating system comprising a plurality of atleast three two-way repeating means each having a line side and a localside, a common multiple having a plurality of at least three taps, andswitching means for connecting each of said taps to a corresponding oneo! said local sides for two-way intercommunication between at least anythree of said repeating means.

5. A signal repeating system comprising a onewire multiple, a pluralityoi' at least three relays each having an operating Winding connected tosaid multiple for response to a spacing potential from said multiple,and contact means connected and operable to apply said spacing potentialto said multiple and simultaneously disconnect one of said operatingwindings from said multiple to prevent response by its relay.

6. A telegraph signal repeating system comprising a local singleconductor, a plurality of relays each having a winding connected to saidconductor, and a plurality of contact means each operable to disconnecta respective one of said windings from said conductor and connect asource of potential to said conductor for operating the other of saidwindings.

7. A local single conductor, a plurality of signal transmitting relaymeans each having a winding in a circuit connected to said conductor,and a plurality of signal receiving relay means each having contactmeans operable to connect a source of potential to said conductor andsimultaneously open one of said circuits thereby operating thetransmitting relays in all the other circuits.

8. A one-wire signaling connection, a rst telegraph signal repeaterhaving a rst relay and a source of marking potential connected through awinding of said relay to said connection, a plurality of telegraphsignal repeaters each having a second relay and a source of markingpotential connected through a contact of said second relay to saidone-wire connection for establishing a low current condition in saidWinding for nonoperaton of said rst relay, and each having a source ofspacing potential connected through the alternate position of said relaycontacts to establish a high current condition in said winding foroperation of said rst relay.

9. A signal repeating system comprising a onewire multiple connected tonormally be at marking potential, a plurality of at least three relayseach having an operating winding connected to said multiple to normallyremain lin marking position, a plurality of contact means each operableto disconnect one of said windings from said multiple to preventoperation of its relay and connect said multiple to alternately be at aspacing potential for operation of the other of said plurality ofrelays.

10. A two-way telegraph repeater comprising a receiving relay havingrepeating contacts for applying alternately a marking potential and adiierent spacing potential to a circuit, and a transmitting relay havingan operating winding connected to said circuit through said contactsonly when said marking potential is applied.

11. A two-way telegraph repeater comprising a receiving relay havingrepeating contacts for applying alternately a marking potential and aaosaavv different spacing potential to a circuit, and a transmittingrelay biased permanently in one direction and having an operatingwinding connected to said circuit only when said marking potential isapplied.

12. A telegraph repeater having aline side and having a local side formultiple operation with the similar local side of a plurality of otherrepeaters for two-way intercommunication between the lines connected tosaid repeaters, the local side of said repeater comprising repeatingcontacts of a receiving relay having a marking and a spacing position,operating winding of a transmitting relay, and a local repeating circuitconnected by said contacts in marking position through said winding tomarking potential, said contacts being operable to. spacing position fordisconnecting said winding from said circuit and connecting spacingpotential to said circuit.

13. A telegraph signal repeating system comprising a plurality of atleast three two-way repeaters each having a line side and a local side,a single-wire multiple having a tap for each of said repeaters andincluding switching means in each of said taps for normal connection ofsaid taps to the corresponding ones of said local sides for two-wayintersignaling between said repeaters and alternate disassociation ofany one of said local sides from said multiple.

FULLERTON S. KINKEAD. GEORGE A. LOCKE.

